Producing zone completions involve insertion of a screen assembly that can be as long as several pay zones with long non-producing formations in between the producing zones. The surrounding annulus around the screens is filled with gravel using a tool called a crossover tool that takes the gravel slurry coming down the tubing string from the surface and redirects it out to the annular space below an isolation packer and outside the screen. The gravel remains in the annular space outside the screens while the carrier fluid goes through the screen and into a wash pipe connected to the crossover. The crossover allows the returning fluid to get through the isolation packer and back to the surface through the upper annular space above the isolation packer.
If the producing zones are far apart, the length of borehole between them is spanned by blank pipe and a packer that allows the screen sections to be properly located at the various producing locations. Typically the delivered gravel goes to the furthest (lowest) screen downhole and fills the annulus around it. When that screen is covered, the crossover tool and wash pipe are shifted to allow the setting of a packer in the annulus (between the two zones) to fully isolate the lower zone before further gravel deposition fills the non-producing zone. After the packer is set, pumping of the slurry is resumed, and gravel is deposited on top of the packer, while the returning fluid finds another path of least resistance and starts going through the next higher production screen as the lowermost screen now fully surrounded by gravel is said to “screen out” or resist flow to an extent that sends the returns to the next higher screen. This technique is illustrated in IACC/SPE 77214 by Corbett and Vickery entitled Multiple Zone Open Hole Gravel Packing Techniques with Zonal Isolation. It is limited to separating two zones with a packer in a single trip but is impractical for more than two zones.
US Publication 2008/0164026 shows a method of gravel packing multiple zones together and then setting packers into the gravel pack to isolate the producing zones.
What is needed and not available is a way to more economically perform a gravel pack of multiple zones that are spaced apart and get a good pack in an intervening non-producing zone while getting effective zonal isolation in the pack between the producing zones without employing packers. Those skilled in the art will appreciate each of the aspects of the present invention, some of which are individually listed above, from a review of the detailed description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be found in the appended claims.